Core rule · Rules Tome 2.0.8 § 106
Skill checks and saves
Roll a d20, add Skill and applicable modifiers, and meet or exceed the DC.
How it works
Full rule
Every save is a skill check, but not every skill check is a save. A bonus to all skill checks applies to saves; a bonus only to saves does not apply to other checks. Checks and saves cannot be voluntarily failed.
At the table
Example
A character with Skill +4 needs a total of 18 against DC 18, so a natural 14 succeeds before other modifiers.
Watch for this
Common mistake
A player cannot choose to fail a save because the failure result would be strategically useful.